Honeywell VISTA Series - Daylight Saving Time (Time Zone Settings)

HoneywellVISTASeriesProductsUserManual
41
1    2      9  10                25  26
EP FC CC OP
Table2DefinitionofFields
Field Purpose
EP
Even Parity bit (EP) isjudged based on field 1to 13 bi t.  EPis 1 if the
numberof"1"iseven;otherwise,EPis0.
FC(bit2bit9)
FacilityCode(0255)
Bit2istheMostSignificantBit(MSB).
CC(bit10bit25) CardCode(065535).Bit10istheMSB.
OP
ThevalueofOddParit ybitisdeterminedby14–26bit.OPis1ifthenum ber
of"1"iseven;otherwise,OPis0.
Pyramid Wiegandformat
Severalalternativesexistforcustomerswhorequiremorecodes.ThefirstistoswitchtoKeri’sstandard39bit
Pyramidformat.This39bitWiegandformatcontains17bitsforthefacilitycodefieldand20bitsfortheID
numberfield.Mathematicallythese17facilitycodebitsallowforatotalof131,072(0to131,071)facilitycodes,
whilethe20IDnumberbitsallowforatotalof1,048,576(0to1,048,575)indiv idualID’swithineachfacility
code.Si ncetherearesomanyfacilitycodesinthePyramidformat,anewfacilitycodemaybeselectedfor
eachproject.Additionally thelargenumberofID’sperfacilitycodemakesthePyramidformati dealforvery
largeprojects.Foraddedsecurity,KeriSystemstrackscredentialcodingtoensurethatnoduplicationoccurs.
Table3providesasummaryofthePyramidWiegandformat.
Table3PyramidWiegandFormat
BitNumber Meaning
Bit1 Evenparityoverbits2to9
Bits2to18 Facilitycode(0to131,071);Bit2isMSB
Bits19to38 IDNumber(0to1,048,575);Bit19isMSB
Bit39 Oddparityoverbits20to38
CustomWiegandFormats
ThesecondalternativeistocreateacustomWiegandformat.Typically,upto64bitsareavailableforcreating
a customWiegand form at.With certain limitations, formats with greater than 64 bits may be created. If a
customercurrentlyhasacustomWiegandformatfromWiegandorfromotherproximitymanufacturers,Keri
cannormallymatchthatformat.Althoughthecustomerisprimarilyresponsibleforcustomformatcardcoding,
asanaddedbenefitKeriSystemstrackscardcodingforadditionalsecurity.Table4providesanexampleof
onepossiblecustomWiegandformat.
Table4ExampleofaCustomWiegandFormat
BitNumber Purpose
Bit1 Evenparityoverbits2to22
Bits2to9 OEMcode(0to255);Bit2isMSB
Bits10to21 Facilitycode(0to4,096);Bit10isMSB
Bits22to43 IDNumber(0to524,287);Bit22i sMSB
Bit44 Evenparityoverbits23to43
10.6DaylightSavingTime(TimeZoneSettings)
TheDaylightSavingTime(DLST)isawidelyusedsystemofadjustingt heofficiallocaltimeforwardtosave
energy.TheuniformtimeadoptedduringtheimplementationofthissystemisknownastheDLST.Typically
clocksareadjustedforwardonehourinthesummertomakepeopleearlytobedandearl ytorisesoasto
makefull use ofillumination resources and save electri city.Clocksareadjusted backwardin autumn.The
specificDLSTregulationsvarywithcountries.Atpresent,theDLSTsystemisadoptedeveryyearbyabout
110countriesintheworld.